Worldwide Interoperability for Microwave Access (WiMAX) is an air interface standard put forward on the basis of IEEE802.16 broadband wireless standards. Currently, the wireless side of the WiMAX network is based on the IEEE 802.16d/e standard. The 802.16d standard defines the Media Access Control (MAC) layer of a fixed broadband wireless access system that supports multiple service types, and defines multiple corresponding physical-layer frameworks. The 802.16e standard adds new functions on the basis of the 802.16d standard to support subscriber mobility.
FIG. 1 shows a reference model of a WiMAX network architecture. A WiMAX network includes three parts: MS or Subscriber Station (SS), Access Service Network (ASN), and Connectivity Service Network (CSN).
The ASN may include a Base Station (BS) and an ASN Gateway (GW); the CSN may include a Prepaid Service (PPS) server, and an Authentication, Authorization and Accounting (AAA) server.
In the existing protocols, the logical entities between the MS/SS, the ASN, and the CSN communicate with each other through interfaces R1 to R6. As shown in FIG. 1, the R1 interface is a wireless air interface, and is primarily defined by the IEEE802.16d/e; the R2 interface is a logical interface; the R3, R4, and R5 interfaces are wired interfaces.
The WiMAX network supports three application scenarios of the MS: fixed scenario, nomadic scenario and mobile scenario. The inventor of the present invention finds that: in the prior art, when the MS is in a fixed scenario or a nomadic scenario, it is unable to manage emergency services of a mobility-restricted MS.